I need some help with the limits of the integrals when you work out the marginal pdf of X or Y.

I've got the formulae

for the marginal pdf of X and

for Y

Then there's the question

Random variables X and Y have joint pdf

where A is the region bounded between and

Looking at the solutions, the limits for f(x) are between and and I think I get that one but for f(y) they're between and which I can't figure out. Can anyone help?